Licorice extract has been shown to inhibit testosterone 5-alpha-reductase, and also androgen receptor binding and antimicrobial activities, which are closely related to sebum secretion. Licorice can help prevent hair loss but should be avoided by pregnant women because of the adverse effects it may have on the developing fetus. If ingested in higher than recommended amounts it can be toxic.

Licorice (Glycyrrhiza glabra), or liquorice as it is known in the UK, is a legume (related to beans and peas), native to southern Europe and parts of Asia. It is an herbaceous perennial, growing to a height of 1 m, with pinnate leaves. The flowers are purple to pale whitish blue and the fruit is an oblong pod, 2–3 cm long, containing several seeds. The flavor of licorice comes mainly from anethole (trans-1-methoxy-4-[prop-1-enyl]benzene), a sweet-tasting compound also found in anise, fennel, and other herbs. Additional sweetness in licorice comes from glycyrrhizic acid, an anti-viral compound more than 50 times sweeter than sugar.

Side effects of licorice

Large doses of glycyrrhizinic acid and glycyrrhetinic acid in licorice extract can lead to hypokalemia and serious increases in blood pressure, a syndrome known as apparent mineralocorticoid excess. These side effects stem from the inhibition of the enzyme 11?-hydroxysteroid dehydrogenase (type 2) and subsequent increase in activity of cortisol on the kidney. 11?-hydroxysteroid dehydrogenase normally inactivates cortisol in the kidney. Therefore, licorice’s inhibition of this enzyme makes the concentration of cortisol appear to increase.

Some researchers have concluded that one gram of licorice root per day is enough to cause potential health problems. As a result, deglycyrrhizinated products are now being manufactured. These new products do not have the same healing properties as their former counterparts, but they are less harmful. In fact, they have proven superior to glycyrrhizinated products for some health conditions such as ulcers, heartburn, cancer sores or skin ailments than the.

Excessive consumption of licorice, or licorice candy, is known to be toxic to the liver and cardiovascular system, and may produce hypertension and oedema. There have been occasional cases where blood pressure has increased with excessive consumption of licorice tea, but such occasions are rare and reversible when the herb is withdrawn. Most cases of hypertension from licorice have been caused by eating too much concentrated licorice candy. Doses as low as 50 grams (2 oz) of licorice daily for two weeks can cause a significant rise in blood pressure.

A study carried out in Iran showed that the administration of 1.3 grams of dry extract of licorice over 10 days diminished testosterone and inhibited sexual desire. Additionally, a study carried out in Finland demonstrated that the consumption of licorice caused premature childbirth.

Licorice should not be used by patients with Type II diabetes, by patients with arterial hypertension or by individuals with low potassium in the blood.

A European Commission 2008 health report suggested that no more than 100mg of glycyrrhizic acid a day should be consumed, because it can raise blood pressure or cause muscle weakness, chronic fatigue, headaches or swelling, and lower testosterone levels in men. Comparative studies of pregnant women suggest that licorice can also adversely affect both IQ and behavior traits of offspring.

Licorice overdose symptoms

Headache can occur due to an increase in blood pressure increase. Edema can occur mainly in the face and in the ankles. The sensation of burning in the extremities, weakness, cramps, dark urine, lost of menstruation, problems with the libido and arrhythmia have also been reported. Symptoms usually diminish quickly if licorice consumption is discontinued.

Health benefits of licorice

There are two types of medicinal licorice: European licorice, Glycyrrhiza glabra, and the Chinese species, Glycyrrhiza uralenis. Only the roots and stems are used.

Licorice as an expectorant

Powdered licorice root is an effective expectorant, and has been used for this purpose since ancient times, especially in Ayurvedic medicine where it is also used in tooth powders. Modern cough syrups often include licorice extract as an ingredient.

Licorice for respiratory problems

Licorice root has anti-inflammatory properties and is used in the treatment of respiratory ailments such as sore throat, cough, cold and asthma.

Licorice as a remedy for gastrointestinal tract problems

Licorice root has antispasmodic and anti-inflammatory properties in relation to the gastric mucosa, which helps to alleviate bloating, indigestion and other more serious bowel conditions such as ulcerative colitis or Crohn’s disease However, it is preparations with DGL licorice (licorice without glycyrrhizin) that have proved to be more effective in counteracting excess stomach acid. This property is useful in treating heartburn and stomachache.

Licorice as a treatment for ulcers

Licorice is used in conventional and naturopathic medicine for both mouth ulcers and peptic ulcers. It has been extensively studied as a possible treatment for ulcers. Studies have shown that licorice prevents the secretion of corrosive gastric acid while reducing pepsin activity. A study of patients suffering from recurring ulcers showed that after 6 weeks of treatment with licorice root, 90% had improved and of those, 24% exhibited complete recovery (Morgan et al. 1982. Gut 23(6):545-551).

Licorice and the liver

The active components in licorice root have been shown to support liver function. Studies involving patients with hepatitis C or liver inflammation indicate that an 80-240 mg per day dose of glycyrrhizin, delivers significant improvements in liver function. After the treatment was stopped, symptoms reverted to pre-study levels (Luper. 1999. Altern Med Rev 4(3):178-188).

Licorice as a laxative

Licorice acts as a mild laxative and may be used as a topical antiviral agent for shingles, ophthalmic, oral or genital herpes.

Licorice for viral infections

The compound glycyrrhizic acid, found in licorice, is now routinely used in Japan for the treatment and control of chronic viral hepatitis. Japanese studies have shown that glycyrrhizin can prevent the growth of viral encephalitis in test tubes. Licorice creams are available which are applied directly to herpes sores three to four times per day.

Licorice and the endocrine system

Licorice contains isoflavones (phytoestrogens) and can affect the body’s endocrine system. It can lower the amount of serum testosterone, but whether it affects the amount of free testosterone is unclear. Consuming licorice is recommended for reducing high sex drive in men. Licorice is believed to be able to prevent hyperkalemia. Licorice can also be used to treat ileitis, leaky gut syndrome, irritable bowel syndrome and Crohn’s disease as it acts as an antispasmodic.

Licorice and age-related mental decline

The compounded carbenoxolone is derived from licorice. Studies indicate that it may inhibit an enzyme in the brain that is involved in making stress-related hormones, which have been associated with age-related mental decline.

Other medicinal uses of licorice

Other uses of licorice include use as a remedy for: inflammation, arthritis,depression, chronic fatigue, kidney problems, fever and allergies.

Licorice and women’s heath

Licorice root contains flavanoids and plant phytoestrogens that have properties similar to estrogen but without the negative side effects normally associated with elevated levels of this hormone. Studies on the effects of the phytoestrogens contained in licorice show it to be a possible remedy for symptoms of PMS, such as bloating, irritability and breast tenderness. Researchers conclude that these phytoestrogens may compensate for the natural decline in estrogen in aging women and as such, defer the effects of menopause.

Licorice external applications

The applications of licorice for external use are based on its capacity to inhibit the growth of viruses, bacteria and fungi.

Licorice dosage

Licorice can be obtained as a chewable wafer, tincture, lozenge, capsule, cream, dried herbal tea and as a liquid. It is advisable to look for licorice that contains a standardized extract of 22 percent glycyrrhizin or those products labeled DGL (deglycyrrhizinated) depending on symptoms. For most health problems, 200 mg of the glycyrrhizinated capsules, taken three times per day is recommended, but the amount will vary according to the symptoms. It is always best to speak with a health professional, especially in cases where there is a history of high blood pressure or if taking diuretics or steroid medications, since licorice may adversely interact. It is also possible that some candies (especially European), chewing tobacco, sodas and cough medicines may contain licorice and if taken in excess, may cause serious problems. However, there are no known side effects for DGL.

Licorice active principles

Licorice contains: Sugars (glycyrrhizin, glucose and sucrose); Flavonoids (licoflavonol, licoricone, glycyrol, glyzarin, formononetin, isoliquiritigenin, glabrol, glabrone); Saponins; Tannins; Betacarotenes; Amino acids (asparagine); Proteins; Acids (salicylic, malic, betulinic, glycyrrhetic, glycyrrizic); Minerals (calcium, chromium, cobalt, phosphorous, magnesium potassium, silicon and sodium); Vitamins (vitamin C, thiamin).

Licorice cultivation

Although Licorice was originally found in parts of Southwestern Asia and Southeastern Europe, today it is extensively cultivated in Russia, India, Persia, Iran and Spain. It also continues to grow wild in Turkey and Greece. One species grows in North America, ranging from Western Ontario to Washington and south to Texas. Licorice grows best in deep, fertile, well-drained soils, with full sun, and is harvested in the autumn, two to three years after planting. Licorice extract is produced by boiling licorice root and subsequently evaporating off most of the water. Licorice extract is traded both in solid and syrup form.